How to make it fully developable?
› DELFTship forum › Hull modeling › How to make it fully developable?
- This topic has 6 replies, 3 voices, and was last updated 1 year, 10 months ago by
jiangrm.
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AuthorPosts
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March 18, 2021 at 08:44 #44031
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March 18, 2021 at 15:54 #44047
Terrance Egolf
ParticipantHello, Jiangrm.
A developable surface must continuously and smoothly curve in one direction, like the front and back halves of your vessel.
The reason the middle is not developable is that it contains a crease edge, which, by definition, has a discontinuous surface curvature. It’s a crease.
You can try removing the crease by selecting all the red edge segments there, then click on the Crease control in the Edge subgroup and see what that does. You may have to add some parallel Normal edges on both sides to smooth out the transition in that area.
Hope this helps.
Terry
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March 18, 2021 at 17:02 #44049
jiangrm
ParticipantHello, Jiangrm.
A developable surface must continuously and smoothly curve in one direction, like the front and back halves of your vessel.
The reason the middle is not developable is that it contains a crease edge, which, by definition, has a discontinuous surface curvature. It’s a crease.
You can try removing the crease by selecting all the red edge segments there, then click on the Crease control in the Edge subgroup and see what that does. You may have to add some parallel Normal edges on both sides to smooth out the transition in that area.
Hope this helps.
Terry
Thank you Terry. I realized that later, cut it in half and it looks good.
The other problem is I want to use a whole flat sheet to make the half hull. Is there any option to unfold it with the keel connected?
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March 18, 2021 at 18:37 #44053
jiangrm
ParticipantHello, Jiangrm.
A developable surface must continuously and smoothly curve in one direction, like the front and back halves of your vessel.
The reason the middle is not developable is that it contains a crease edge, which, by definition, has a discontinuous surface curvature. It’s a crease.
You can try removing the crease by selecting all the red edge segments there, then click on the Crease control in the Edge subgroup and see what that does. You may have to add some parallel Normal edges on both sides to smooth out the transition in that area.
Hope this helps.
Terry
Removed crease of the edges in the middle, the whole hull turned red 😀
Well my goal is to develop a canoe hull that is fully developable. It looks seemingly possible with the paper model but I couldn’t prove/disprove it geologically. Is there any way to do that?
In any case if impossible, making hull in halfs is an acceptable compromise.
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March 19, 2021 at 03:21 #44057
Terrance Egolf
ParticipantYeah, well that didn’t work, did it? I was afraid that would happen.
You might consider a using a band of the appropriate width wrapped around the middle of the boat, which will be developable, with your two developable ends. You will have two crease edges this way, but it will look more like your paper conceptual model.
Another approach would be to use long strips the length of the hull, like planks, with creases between them. That involves a different construction method, however.
Terry
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March 19, 2021 at 08:09 #44058
Maarten
KeymasterAs a consideration: your canoe design (with a smooth hull) can never be fully developable, as the surface curves in more than one direction (hence the red color in plate development). Not that it is impossible to create it from plates, but it will depend greatly on the properties of the plate.
If you want fully developable plates, consider making a lapstrake construction.
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March 20, 2021 at 04:16 #44059
jiangrm
ParticipantIt will be a take-down lightweight canoe. In this case, my priority is material and simplicity of manufacturing. I wanted to use (ideally) a whole sheet of plastic film (very likely non-stretchable but possibly slightly stretchable) for the hull.
Taping it in the middle is ok but not preferable as it increased the risk of leak.
If calculating developability is possible from the curvature, is there any way to set developability as a constraint when moving the points around (like limiting the movement in one axis/plane)?
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